[TUHS] Tandem NSK implementation language (was: Happy birthday, John Backus!)

[Paul McJones]

> On Dec 4, 2018, Greg 'groggy' Lehey <grog at lemis.com> wrote:
> 
> The original Tandem OS (called Guardian at the time) was written in Tandem's TAL (Transaction Application Language, amongst other productions), a vague evolution of HP's SPL that looked more like Algol, starting in about 1974.  That is also the earliest I know of an operating system being implemented entirely in a high level language.

Most likely the earliest operating system written in a high-level language was the one for the Burroughs B5000 (early 1960s), written in a dialect of Algol 60. Others: Multics, written in PL/1 (starting in mid 1960s), the  operating system for the Berkeley Computer Corporation’s BCC-500, written in BCC SPL (system programming language) (late 1960s), OS6 by Stoy and Strachey, written in BCPL (early 1970s), Xerox Alto OS, written in BCPL (about 1974).